Create filters for nested classes.

[doandreas]

Thank you for open sourcing a library like this. 👍

I guess from the implementation its not supported to create filters for nested classes right ? I saw a related PR but just to be sure.

Example :

class Person {

name : string ,

address : Address

}

class Address {

postcode:sting,

address:string

}

in order to create a filter like address_postcode_like = "1234"

[pgrund]

Hi,
I assume your classes are type classes (@ObjectType) ...
I actually do something quite similar (but way more complex) in one of my projects ... so let me share my approach

typescript example:

@ObjectType
export class Person {
  @Field(type => String)
  @Filter(["eq","like"], type => String)
  name: string;
  address_ref: string
}

@ObjectType 
export class Address {
 @Field(type => String)
 @Filter(["eq","like"], type => String)
 postcode:string;

 @Field(type => String)
 address:string;
}

@Resolver(Person)
export class PersonResolver { 
  @FieldResolver(
  address(@Root() person: Person, @Ctx() context): Address {
    return person.address_ref && context.adresses.getByRef(person.address_ref);
  }
}

@InputType()
export class FilterOnPerson extends createFilterType(Person) {
   ​resolver?: PersonResolver;
   constructor(propMap: object = {}) {
        super();
        this.resolver = new PersoResolver();
        Object.getOwnPropertyNames(propMap).forEach(name => {
            this[name] = propMap[name];
        })    
    }

   @Field( type => FilterOnAddress )
    address: FilterOnAddress
} 

That allows me within my filter function to delegate filtering to a FilterOnAddress, doing something like

...
switch(field){
    case "address":
        let aFilter = <AddressFilterType>value;
        predicate = ((person: Person, _1, _2) => {
            let address = this.resolver.maintainer(person, context);
            return address && aFilter.filter(context, address);
        })
....

not runnable and a lot of code left out, but I hope it shows the idea ...